1. Field of the Inventions
The present inventions relate to power transmitting apparatuses for switching between 2-wheel and 4-wheel modes and locking and unlocking differential devices.
2. Description of the Related Art
Four-wheel buggies, also known as “ATVs” (All Terrain Vehicles), usually include power transmitting apparatuses for connecting and disconnecting power from an engine to the front wheels, which are not-driven wheels, and also switching between 2-wheel and 4-wheel drive modes. Such a vehicle is disclosed in Japanese Laid-open Patent Publication No. 191768/2003.
Generally, the power transmitting apparatus is provided with a differential means (differential gear set) to provide smooth turning of vehicle by absorbing the difference of rotation between left and right wheels. Japanese Laid-open Patent Publication No. 509409/1994 discloses another type of differential system that does not a differential gear set.
Some known designs can limit the differential action of one wheel by incorporating a power transmitting apparatus provided with means for locking the differential means (differential-locking means) in order to prevent a reduction of driving torque under circumstances in which one of left and right wheels of vehicle would be mired in a slippery road such as mud. A more recently proposed design of a power transmitting apparatus include a motor for connecting and disconnecting the driving force and locking and unlocking of a differential means.
For example, one prior art power transmitting apparatus includes an electric motor arranged in either of the left or right sides of a case forming a box of the power transmitting apparatus. The connection and disconnection between an input shaft connected to an engine and an output shaft connected to a front wheel as well as the locking and unlocking of a differential means are performed by actuating a fork connected to an actuator driven by the electric motor.